The present invention relates to a battery charging device capable of charging a plurality of batteries with a single device.
Battery packages accumulating rechargeable batteries that can be repeatedly used are recently being employed as power sources of power tools. By providing a plurality of such battery packages, the power tools may be successively used.
However, in case the battery packages are used by a plurality of numbers, it may happen that one cannot distinguish whether each of these are charged or run down battery packages. It may thus happen that already charged battery packages are again charged to thereby shorten the life of the batteries and to unnecessarily lengthen the time for charging. On the other hand, in case run down batteries are left uncharged, operations using power tools may be interrupted owing to battery exhaustion.
In order to cope with such problems, it has been materialized for a method of discriminating capacities of battery packages by mounting ICs for detecting and integrating charge/discharge currents within battery packages. However, mounting ICs to each battery package caused increases in costs and also lead to large-sized battery packages.
The present invention has been made for the purpose of solving the above subjects, and it is an object thereof to provide a battery charging device capable of displaying that a capacity of batteries is not less than a specified level without mounting ICs to battery packages for current detection.
In order to achieve the above purpose, a battery charging device according to the present invention is characterized by comprising:
judging means for judging, prior to start of charge, whether an open-circuit voltage of batteries is higher than a specified value, and
indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the battery voltage is higher than the specified value.
In a battery charging device, it is determined whether an open-circuit voltage provided by batteries is higher than a specified value, and in case the voltage of the batteries is higher than the specified value, it is displayed that a capacity of the batteries is not less than a prescribed value. It is thereby possible to discriminate before starting charge whether the batteries need to be charged or whether they do not.
A battery charging device according to the present invention is characterized by comprising:
an open-circuit voltage obtaining means for obtaining, based on an identifier provided on the battery side, an open-circuit voltage at the time the battery capacity is not less than a specified value,
judging means for judging, prior to start of charge, whether a measured open-circuit voltage of batteries is higher than the open-circuit voltage as obtained by the open-circuit voltage obtaining means, and
indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the measured open-circuit voltage is higher than the obtained open-circuit voltage.
In a battery charging device, it is determined whether an open-circuit voltage provided by batteries is higher than a specified value, and in case the voltage of the batteries is higher than the specified value, it is displayed that a capacity of the batteries is not less than a prescribed value. It is thereby possible to discriminate before starting charge whether the batteries need to be charged or whether they do not. On the other hand, by acquiring an open-circuit voltage when the capacity of the batteries is not less than the specified value on a basis of an identifier provided on the battery side, it is enabled to determine whether the batteries of various voltages satisfy a specified capacity or not.
A battery charging device according to the present invention is characterized by comprising:
a memory means for storing maps, which are maps that are obtained through mapping based on temperatures and values of rises in temperature of batteries to obtain a permissible current value at which charge may be performed while restricting a rise in temperature of batteries, for setting the permissible current value to be small in case the temperature value is high and setting the permissible current value to be small in case the temperature rising value is low,
a temperature detecting portion for detecting a present temperature of the batteries,
a temperature rising value outputting means for obtaining the temperature rising value from the temperature as detected by the temperature detecting portion,
a permissible current value retrieving portion for retrieving maps in the memory means for obtaining the permissible value based on the temperature as detected by the temperature detecting portion and the temperature rising value output by the temperature rising value outputting means,
a charging portion for charging the batteries at the permissible current as retrieved by the permissible current value retrieving portion,
a capacity judging portion for judging whether the batteries have been charged up to a specified capacity on a basis of judgments whether a number of times in which the temperature as detected by the temperature detecting portion and the temperature rising value output by the temperature rising value outputting means fall within regions indicating a final stage of charge from among the map of the memory means is frequent or not, and indicating means for indicating that a capacity of the batteries is not less than a prescribed value based on the judgments of the capacity as obtained by the capacity judging portion.
In a battery charging device, a permissible current value at which charge may be performed while restricting a rise in temperature of batteries is obtained by using a map that is obtained through mapping temperature values of batteries and values of rises in temperature of batteries. More particularly, a map is retrieved based on temperatures and values of rises in temperature of batteries to obtain a permissible current value at which charge may be performed while restricting a rise in temperature of a battery, and the batteries are charged at the permissible current value. It is accordingly possible to charge batteries, which temperatures are apt to rise at the time of charging, in a short time while causing no degradations owing to rises in temperature.
It is particularly possible to perform accurate determination without being affected through periphery temperatures or the like since it is determined whether the capacity of the batteries is not less than the prescribed value by using the map for determining whether a number of times in which the temperature rising value is relatively high and in which relatively small permissible current values are output is frequent or not, that is, whether the rise in temperature is high and whether the rise in temperature is still being high also when setting a value of charge current to be small.
In accordance with the more preferred teaching of the present invention, the battery charging device is further characterized by comprising: an integrating means for integrating charge currents to the batteries, and
an integrated value judging means for judging whether charge has been performed up to a specified capacity by the integrating means,
wherein one of the indicating means indicates that a capacity of the batteries is not less than a prescribed value in case it is judged by the integrated value judging means that charge has been performed up to the specified capacity.
In a battery charging device, it is being displayed that the capacity of the batteries is not less than the prescribed value by integrating the amount of charge current to the batteries so that it is possible to reliably perform display.
A battery charging device according to the present invention is characterized by comprising:
a charge amount storage means for storing charge amounts to a memory means of the batteries during charging,
judging means for judging, prior to start of charge, whether an open circuit voltage of batteries is higher than a specified value, and
indicating means for indicating that a capacity of the batteries is not less than a prescribed value in case the battery voltage is higher than the specified value and the charge amount as stored in the memory means is high, and for indicating that a capacity of the batteries is not more than the prescribed value in case the charge amount as stored in the memory means is low though the battery voltage is higher than the specified value.
In a battery charging device, charge amounts are stored in a memory device of the batteries during charging. Prior to starting charge, in case a voltage of the batteries is higher than a specified value and the amount of charge stored in the memory device is high, it is displayed that the battery capacity is not less than a prescribed value. On the other hand, in case the battery voltage is higher than the specified value but the amount of charge stored in the memory device is low, it is displayed that the battery capacity is the prescribed value or less. It is therefore possible to appropriately display that the battery capacity is the prescribed value or less even immediately after the batteries have been charged for a short time and the battery voltage has thus been temporarily increased.